Process of removing water from petroleum oil



July 6 1926.

W. J. MaCARTHUR PROCESS OF REMOVING WATER FROM PETROLEUM OIL Filed May17, 1923 Patented July 6, 1926.

y 1,591,853 PATENT OFFICE.

UNITED STATES WILLIAM J. IIAQARTIIUR, oF Los ANGELES, CALIFORNIA,AssIGNon or ONE-HALF To REA E. MAYNARD.

RO'CESS 0F REMOVING- WATER FROM PETROLEUM OIL.

' Application led May 17, 1923. Serial No. 639,722.

My invention relates to the art of separating water from oil. 'In theproduction of petroleum oil wells are often encountered which produce inaddition to large volumes of oil, considerable volumes of.water. Ifthese wells How under considerable pressure, as is usually the case withlarge productive wells, it is a common practice to restrict the flowafter the oil leaves the well for the purpose of preventing the wellfrom sanding up, due to excessive movement of gas and oil. The well iscommonly `re strained by passing the fluid through a constricted orificein which a trap under pres-l sure of several hundred pounds per squareinch may occur. If a mixture of oil and water is passed at a highvelocity through such a constricted orifice, the water and oil are sobroken up and mingled that they form an emulsion, the water commonlyappearing as free, fine particles suspended in'the body of oil. Theseemulsions are extremely difficult to separate. It is a well known factthat the water and oil in these high pressure wells is not in the formof an emulsion, and if the water and oil are separated before thepressure is released thereon, emulsions will not be formed.

It-is an object of my invention to provide a novel process of separatingthe oil and water for the purpose of preventing the formation ofemulsions., My invention involves a novel method of separating water andoil and while it is described as applying to a particular purpose,namely, the separation of petroleum oils and water as they come from anoil well, it is to be understood that my invention-is not restricted Vtothis particular application since it can beapplied to any use in whichit is desired to separate oil and water. i

Further objects and advantages will be made evident hereinafter.

Referring to the drawings which are for.

illustrative purposes only,

Fig. 1 is a side elevation partly in section of a complete apparatusattached to separate oil from water as it comes from an oil well;

gig., 2 is a section through the separator; an I Fig. 3 is a section ona plane indicated by the line 3-3 of Fig. 2.

In the embodiment of my invention shown I employ a settling chamber 11,from which Huid to the casing hea-d 12 is delivered, in con]unction witha novel form of water separator 13 and a fluid trap 14. The settlingchamber 11 may conveniently be con- A structed of several joints oflarge pipe .connected together and placed on an Incline so that the end20 is higher than the end 21. The oil delivery pipe 22 enters throughthe end 20 and passes to a point 23 inside the settling chamber. The oiland gas takeoff pipe 25 is connected into the top of the sett ingchamber 11, preferably above the point 23. The pipe 25 is provided witha gauge 26, a hand operated valve 27 and an automatic pressureregulating valve 28. The water separator 13 consists of an outer shellor casing 30, having a cover 31 secured thereto by bolts 33, a gasket 34being provided between the casing 30 and the cover 31. Secured to thecover 31 inside the casing 30 is a casting 35, which is secured to thecover 31 by the bolts 36, a gasket 37 being provided between the cover31 and the casting 35. Secured to the casting 35 by means of bolts 40are a plurality of annular rings 41 and a cover 42. Thin metal washers43 are placed around the bolts 40 between-the lates 41, acting as shimsto separate the ates 41 by auniform but small distance. Oil and waterare delivered to the space inside the casting 35 from the bottom of thesettling chamber 1l by means of a pipe 50 having a valve 51. Oil isdelivered from the top of the space inside the castin 35 through a pipe52, having a valve 53 to tJ e settling chamber, at a point preferablyabove the point 23. A gas equalizing pipe having 'a valve 61 extendsfrom the casing 30 up into the extreme top ofthe settling chamber 11. Awater outlet pipe 7 0 having a valve 71 extends from the bottom of thecasing 30 to the trap 14. The trap 14 is a standard steam trap, that isit is a device which is so arranged that any liquid passing into thetrap 14 from the pipe is delivered to a pipe 72.

The method of Operation is as follows: The mixture of oil, water and gasfrom 'the casing head 12 passes through the pipe 22 into the settlingchamber 11, in which the water tends to settle to the bottom, and thegas and oil tend to rise to the top. A pressure is maintained on thesettlin chamber due to the regulating valve 28 w ich regulates the flowof gas and oil from the top of the trap so that a uniform and constantpressure is maintained on the settling chamber 11 and on the casing head12 of the well, this uniform pressure being desirable to prevent injuryto the wall through too violent movement of oil and gas therein. The oiland gas delivered through the pipe 25 may be passed throu h a standardoil and gas separator, not s own, to separate the gas from the oil ifdesired, and this may be accomplished` either before or after thepressure is relieved. The water which settles in the bottom4 of thechamber 11, near the end 21, passes downwardly 'through the pipe 50 intothe space'inside the casting 35. The

casting 35 and the rings 41 with the cover 42 form a closed containerhaving small openings in the walls thereof, that is, through the smallopenings between the rings 41. The walls of these openings having firstbeen wet with water in starting the device are so narrow that thefilm`of water formed therein .resists the intrusion of oil, the actionprobably depending upon the surface tension of the water or oil, so thatwater will flow readily through these Small openings but oil is excludedtherefrom. To prevent an excessive pressure being placed upon thesewater films, I provide a gas equalizing pipe which supplies a pressureat all times to the space inside the casting 30, and equalizes the gaspressure o n either end of the film of water. In practice the waterflows very freely through the openings between the plates 41, and isvdelivered through the pipe to the trap 14, by which it is automaticallyVdischarged as it collects to the pipe 72. Any oil entering the spaceinside the casting 35 rises in this space andtends to flow back, due toits greater buoyancy, through the pipe 52 and into the upper portion ofthe settling chamber 1l. 'If at any subsequent time no more water isdelivered from the pipe 50, all flow through the space between theplates 41 ceases, but the water film between the plates will prevail sothat at no time is any oil delivered to the pipe 7 0. My inventioninvolves a new process or method of removingwater from oil by the use ofwhat may be .termed capillary films, that is, films between water-wettedsurfaces which are so thin that they resist any intrusion of t oil,acting as automatic means for draining water from a container andpreventing the escape of oil therefrom. In actual practice I have foundthat the most effective degree of separation of the several plates orrings is in fact dependent `somewhat upon the material of which they aremade, their width (which determines the length of the respectivecapillary passages) and the character of the oil. Certain tests provedthat with rin' s constructed of brass and having a wi th 'of` two andone-half inches, efficient separation of water from oil of 34 gravitytest was effected with the rings relatively spaced a distance ofapproximately one-hundredth of an inch apart. While I have shown myinvention applied to yan oil well 'for the purpose of separatingcapillary water film in said opening and thereafter submitting the oiland water mixture to the separating action of said capillary opening. ci

2. The method of separatin oil from a mixture of oil and water whiccomprises: establishing two independent surfaces sufficiently near toeach other to form a capillary opening of uniform width; establishing acapillary water film in said opening and thereafter submitting the oiland Water mixture to the separating action of said capillary opening.

3. The method-of separating oil from al mixture of oil and water whichcomprises: making a surface ordinarily pervious to oil andwaterimpervious to oil while remaining pervious to water by establishinga film of water over such surface and exposing the mixture to theseparating action of treated surface.

l4. The method of making a filter having capillary openings ordinarilypervious to oil or water lmpervlous to o1l whlle remam-` ing pervious towater, which comprises: subjectlng the capillary openings to a film ofwater.

5. The method of making a filter having capillary openings ordinarilypervious to oil and water impervious to oil while remaining pervious towater whichv comprises: establishing a film of water over the capillaryopenings.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 9th day of May, 1923. l I

. WILLIAM J. MAGARTHUR.

